Orthoseira roeseana

(Rabenh.) Pfitzer 1871      Category: Centric
BASIONYM: Melosira roeseana Rabenh. 1853

Odontidium mesodon


Oxyneis binalis

LM scalebar = 10 µm = 40 pixels.


Contributor: Mark Edlund | David R.L. Burge - July 2017
Diameter: 22.1-50.5 µm
Rows of areolae in 10 µm: 6.4-7.1 based on circumferential density


Frustules are heavily silicified and aligned in short filaments of 2-10 cells adjoined face-to-face by short conical or flattened spines. The spines are regularly spaced along the face-mantle junction. Frustules are 39.7-51.1 µm long in the pervalvar axis. The base of the spines extend onto the mantle and may continue for a short distance onto the valve face. The mantle is broad. In smaller cells, the mantle height is relatively larger. Valves have a flat to slightly convex face. Valves have a small central area with 2-5 carinoportulae, a type of pore specific to the genus Orthoseira. Valve face areolae are arranged in radial striae that end in small furrows formed by adjacent spine bases near the face-mantle junction. Valve face areola density is 14.5-19.3 in 10 µm. The valve mantle has straight pervalvar striae (16.4-19.3 in 10 µm) with areola density 13.5-17.5 in 10 µm. Frustules with a broad cingulum. Girdle bands are variably ornamented with pervalvar rows of fine areolae.

The genus Orthoseira is recognized as needing monographic treatment to resolve the typification, taxonomy, and nomenclature of its common forms—roeseana, dendroteres, dendrophila, tatrica, circularis, americana, epidendron (Houk 1993, 2003, Spaulding and Kociolek 1998), which is complicated by the great morphologic variation within current taxa. Here, we follow the broad concept taxonomy for O. roeseana of Houk (2003).

Original Description

Basionym: Melosira roeseana
Author: Rabenh. 1853
Diameter: 20 µm
Rows of areolae in 10 µm:

Original Description

Original Images

Cite This Page:
Edlund, M., and Burge, D. (2017). Orthoseira roeseana. In Diatoms of the United States. Retrieved April 25, 2018, from http://westerndiatoms.colorado.edu/taxa/species/orthoseira_roeseana

Species: Orthoseira roeseana

Contributor: Mark Edlund | David R.L. Burge

Reviewer: Sarah Spaulding


Foged, N. (1981). Diatoms in Alaska. Bibliotheca Phycologica, Band 53, J. Cramer, Vaduz, 317 pp.

Houk, V. (1993). Some morphotypes in the Orthoseira roeseana complex. Diatom Research 8(2): 385-402. 10.1080/0269249X.1993.9705269

Houk, V. (2003). Atlas of Freshwater Centric Diatoms with a Brief Key and Descriptions. Part I. Melosiraceae, Orthoseiraceae, Paraliaceae and Aulacoseiraceae. Czech Phycology Supplement, Volume 1, Czech Phycological Society, Olomouc.

Pfitzer, E. (1871). Untersuchungen über Bau und Entwicklung der Bacillariaceen (Diatomaceen). Botanische Abhandlungen aus dem Gebiet der Morphologie und Physiologie. Herausg. von J. Hanstein, Bonn. 1(2): 189 pp.

Rabenhorst, L. (1853). Die Süßwasser-Diatomaceen (Bacillarien) für Freunde der Mikroskopie. Leipzig, 72 pp.

Roemer, S.C. and Rosowski, J.R. (1980). Valve and band morphology of some freshwater diatoms. III. Pre- and post-auxospore frustules and the initial cell of Melosira roeseana. Journal of Phycology 16(3): 399-411.

Sheath, R.G. and Steinman, A.D. (1982). A checklist of freshwater algae of the Northwest Territories, Canada. Canadian Journal of Botany 60: 1964-1997.

Spaulding, S.A. and Kociolek, J.P. (1998). The diatom genus Orthoseira: ultrastructure and morphological variation in two species from Madagascar with comments on nomenclature in the genus. Diatom Research 13: 133-147.

Stoermer, E. F., Kreis Jr, R. G., and Andresen, N. A. (1999). Checklist of diatoms from the Laurentian Great Lakes. II. Journal of Great Lakes Research 25 (3), 515-566.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA

California Academy of Sciences (CAS)

Orthoseira roeseana CAS

North American Diatom Ecological Database (NADED)

NADED ID: 74001

Autecology Discussion

Orthoseira roeseana is an aerophilic species found on wet walls and moist subaerial habitats. It is found across a broad latitudinal gradient, from small ponds in Alaska (Foged 1981) to subaerial habitats in Ohio (this material and Roemer and Rosowski 1980), the Great Lakes (Stoermer et al. 1999), the Northwest Territories (Sheath and Steinman 1982) and subtropical regions (Spaulding and Kociolek 1998).


Girdle view of filament, at two levels of focus (Science Museum of Minnesota MBE 825A).

Credit/Source: M. Edlund

Girdle view of filament, showing the silica spines that join frustules together (Science Museum of Minnesota MBE 825A).

Credit/Source: M. Edlund

Low magnification image of a large number of Orthoseira roeseana filaments (Academy of Natural Sciences of Drexel University GC3441).

Credit/Source: S. Spaulding